George h



{No Model.)

v G. H. COOPER.

AIR MOTOR.

No. 593,923. Patented Nov. 16, 1897.

WITNESSES I /N VE N 70/? A TTOHNEYS.

UNITED STATES PATENT mar.

GEORGE H. COOPER, OF NEW WESTMINSTER, CANADA.

AlR-MQTOR.

SPECIFICATION forming part of Letters Patent No.'593,'923, datedNovember 16, 1897.

Application filed April 14, 1897.

, act description.

My invention relates to air-motors, particularly such as are employed.for propelling street-cars. v v

The object of my invention is to provide an air-motor in which acompound effect may be obtained, the air being used at the same pressureit has in the reservoir. Provision is also made for applying air underthe same pressure to two or more pistons after the pressure in thereservoir has fallen so much as to render a compound effectimpracticable or uneconomlc.

Another object of my invention is to utilize the surplus power notrequired for propulsion to operate a compressor for the purpose ofpartly replenishing the supply of air in the reservoir. I also provideimproved means for governing the speed of the motor. The compressorabove referred to also forms a very efficient brake.

The features of construction whereby the above-indicated results areobtained will be fully described hereinafter and the novelty pointed outin the appended claim.

Reference is to be had to the accompanying drawing, which is alongitudinal section of an air-motor constructed according to myinvention.

A is the supply-pipe connected to the airreservoir. (Not shown.)

B is a throttle-valve or other suitable valve located in thesupply-pipe, said valve being operated to start or stop the motor.

The supply-pipe A leads tofthe chest 0, in which moves the slide-valve Dof the highpressure cylinder E, having inlet-ports E and anexhaust-poptflsubstantially like those of an ordinary steam-engine. Theexhaustport E is connected by a pipe or channel F to the chest 0 of theslide-valve D, controlling the admission of air to the second or me-'dium-pressure cylinder E". This cylinder is of larger diameter than thehi gh-pressure cylinder E. The exhaust-port E of the second cylinder is.connected by a channel or pipe F $eria1 No. 632,101. (nomad) cylinder Jof an air-compressor,said-compressor having port-s K K at its upper end,which ports are connected by means of pipes L to the supply-pipeA at apoint between the reservoir and the valve B. The pipes Lhaveoutwardly-opening check-valvesM. Between said valves and the ports K Kthe pipes L are connected to branch pipes N, having inwardly-openingcheck-valves O, and the two pipes N are connected into one, as shown atN, their connection with the atmosphere beingcontrolled by a valve P,placed within ready reach of the operator. The supply- -pipe A is alsodirectly connected to the slidevalve chests O and O of themedium-pressure and low-pressure cylinders E and E respectively, theconnection being efiected by means of pipes Q and controlled by valvesQ, so that the compressed air may be admitted to the cylinders E and Edirectly from the supply-pipe A, if desired.

The operation of my air-motor is as follows: The valve B being openedand the valves Q closed, air is admitted to the highpressure cylinder Eunder the same pressure it has in the reservoir. The air operates thepiston H in the well-known manner and then escapes through the pipe F tothe mediumpressure cylinder E, where it operates the piston H andfinally travels in a like manner-through the pipe F into thelow-pressure cylinder E, whence it escapes to the atmosphere afteractuating the piston H The reciprocating piston-rod I actuates thepiston H of the compressor, forcing the air from the cylinder'J at eachstroke through one of the, pipes L to the air-reservoir. At each strokeair is drawn into the cylinder J through one of the pipes N, and byopening the valve P more or less the operator can control the resistance opposed to the motion of the piston H and thereby regulate thespeed of the car.

It will be understood that the compressor is operated only by the excessof power above that required for propulsion. The compressor will act asa brake, particularly on a downgrade, and will, moreover, partlyreplenish the supply of air in the reservoir.

It will be evident that the air is used expansively in the cylinders Eand E the motor shown being thus a triple-expansion motor. The sameconstruction could of course be applied as well to a motor having two,four, or more cylinders receiving the air successively.

When the pressure in the reservoir becomes so low that little or nopower is obtained by expansion in the low-pressure cylinder E, I openthe valve Q, leading to the mediumpressurc cylinder E so that the pistonH (of larger area than the piston H) becomes the high-pressure pistonand only the cylinder E is a compound cylinder. Aftera further reductionof pressure in the reservoir air may be admitted directly to the largestcylinder E The advantages of myimproved motor are an economicutilization of the air at the reservoir-pressure, dispensing with areducingvalve, an easy control of the speed, a powerful brakingaction,the change from compound to direct action as the pressure fallsin the reservoir, and the partial replenishing of the air-supply. Byconnecting the pipe L to the supply-pipe A instead of directly to thereservoir I secure the advantage that the heated air from the compressorenters the motor-cylinders first, and thus prevents the formation ofice.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- An air-motor having a cylinder and a piston therein,an air-supply channel connected to said cylinder, a compressor operatedby said piston, and a valved compressed air-channel leading from saidcompressor directly to the air-supply pipe to partly replenish thesupply of air, substantially as described.

GEORGE ll. COOPER.

WVitnesses: v

CHARLES E. RoBsoN, JAMES G. SMITH.

